Apparatus for separating defective sheets as sheared from continuous strip



Dee. 30, 1947. R L DQWELL 2,433,685

APPARATUS FOR SEPARATING DEFECTIVE SHEETS AS SHEARED FROM CONTINUOUS STRIP Filed Nov. 5. 1943 4 Sheets-Sheet l Dec. 30, 1947. R. DowELL APPARATUS FOR. SEPARATING DEFECTIVE SHEETS 4 sheets-sheet 2 AS SHEARED FROM CONTINUOUS STRTP Filed Nov.A

Dec. 30, 1947. R, DQWELL 2,433,685

APPARATUS FOR SEPARATING DEFECTIVE SHEETS y AS SHEARED FROM CONTINUOUS STRIP Filed NOV. 3, 1945 4 Sheets-Shea?.- 3

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DBC 30, 1947,- R. L. DowELL APPARATUS FOR SEPARATING DEFECTIVE SHEETS AS SHEARED FROM CONTINUOUS STRIP Filed Nov. 4 Sheets-Sheet 4 Patented Dec. 30,1947

APPARATUS FOR SEPARATING DEFECTIVE SHEETS AS SHEARED FROM CONTINUOUS STRIP Ralph L. Doweli, Birmingham, Ala., assignor to Tennessee Coal, Iron and Railroad Company, Birmingham, Ala., a corporation of Alabama Application November 3, 1943, Serial No. 508,850

Claims.

The present invention relates broadly to metallic sheet classifiers, and more particularly to an improved electrical detector and control for segregating prime metal sheets from defective sheets having pin-holes or like defects therein, and means for conveying the prime sheets to one station and the defective sheets to another station.

`More specifically, the invention is directed to a novel combination of coordinated mechanical and electrical instrumentalities, including means for feeding continuous strip, a rotary or flying shear for cutting the strip into sheets of desired predetermined lengths, a sheet classifier comprising one station adapted to receive prime sheets and another station adapted to receive sheets with pin-holes or like defects therein, there being respective conveyors for delivering the sheets to each of said stations, the routing of the sheets being under control of a defiector gate effective in one position to direct them to the conveyor serving the prime sheet station and in another position to the conveyor serving the defective sheet station, said defiector gate being under control of a. pin-hole detector which is responsive to light rays adapted to penetrate a pin-hole or similar defect in the strip, the deilector being actuated by a solenoid or equivalent electrically powered element, the operation of the deiiector being governed with great precision by novel control instrumentalities constructed and arranged to energize said electrically powered element after a pin-hole or defective portion of the strip has traveled, at a high speed, a predetermined distance beyond said pin-hole detector and reached a definite position with respect to the cutter blade on the shear drum which severs the strip into sheets.

For a more complete understanding of the invention, reference should be made to the following detailed disclosure, the accompanying drawings, and the appended claims.

In the drawings:

Figure 1 is a view partlyin side elevation and partly in section, illustrating the principal elements oi' a classifier and related equipment embodying the present invention.

Figure 2 is a plan view of Figure l.

Fi'gure 3 is a diagram schematically i11ustrating the essential elements of the herein claimed invention and showing the coordination between the mechanical and electrical instrumentalities for controlling with great precision the deflecting means which routes sheets to either the prime sheet station or the defective sheet station.

Figure 4 is a detail view of a timing device.

Figure is a section on line V-V of Figure 4.

Figure 6 is a detail view of a make-and-break contact device driven by the shear.

Figure '7 is a diagram similar to Figure 3, illustrating an alternative embodiment of the invention.

Referring in detail to the drawings, l0 represents a sheet piler herein referred to as a prime sheet station, adapted to receive perfect sheets delivered thereto by a belt conveyor ii, and I2 represents a rack or box adapted to receive defective sheets, delivered thereto by a belt con-.- veyor i3, such as sheets having pin-holes or other defects therein. Metallic sheet stock S in continuous strip form is fed by a roller leveler it of conventional construction to a rotary ilying shear comprising rotary drums l-l having blades i'i which coact to shear the strip to thus form a plurality of separate sheets of predetermined desired lengths. Prior to the time the strip reaches the shear, it passes a pin-hole detector indicated as a whole at i8. This detector is of conventional form, and comprises a housing containing a plurality of exciter lamps one of which is indicated diagrammatically at 20. These lamps are adapted to pass rays of light l through pin-holes or other openings or lightpervious defects in the strip. The light beam penetrating the pin-hole or similar defect acts on a conventional photoelectric cell contained in the housing 22. This4 generates a current which is amplified by a conventional amplifier 24 which, in turn, acting through a thyratron control elemerit 28 contained in the cabinet 28, energizes the coil 30 of relay 32. Relay 32 closes contacts 34, which complete a circuit across the -cycle 220-volt power supply lines 33-35, thus energizing the actuating solenoid 36 of a pinwheel timer 38. plurality of pins 40 which can be set by solenoid 36 to a position to actuate a switch 5B hereinafter referred to.

The length of time for whichrelay 32 remains energized is under control of a conventional thyratron tuning device including relay 4I whose contacts 42 when openeddeenergize coil 30 ci relay 32 after the lapse oi time necessary to cause solenoid 38 to depress pins 40 of timer 38. Since this relay 4I is a conventional Westinghouse time delay rela'y of a type well known to those skilled in the art as an electronic timer, it will not be further described or illustrated. It is well suited for controlling very short interval timing. Its operation depends upon the time This timer includes a rotor 39 carrying e the shear drum IEB.

interval required to charge a condenser assoelated with a known type of thyratron tube which causes said tube to become conducting. When the thyratron tube becomes conducting, it energizes the relay 4I The function of the timer 38 is to measure the linear amount of strip passing a given point per unit of time. For example, the timer can measure the feet of strip passing a given point per minute or for a definite number of revolutions of the roller leveler. The timer is conveniently driven through a suitable gear reduction unit 48, shown in Figure 4, i'rom the roller leveler I4, as shown diagrammatically in Figure 3.

When an impulse from the amplifier of the pin-hole detector I8 energizes coil 30 oi' relay 32, its contacts 34 close. Thus a circuit through power source 33 is closed across said contacts 34 through the timer actuating solenoid 36. This causes a plunger 31 to move forward and strike one of a circular ,series of pins 4IJ carried by the rotor 39 of the timer. The pins are held projected outwardly from one face of the rotor about 1/4 inch as long as the solenoid 36 remains energized. The rotor eventually turns the projected pin or pins to a position where it or they actuate a switch 56 effective to close a circuit across power supply lines 51 and 58 through a relay 68.

The time; pins described provide a proportional time control delay device, since the fraction of a revolution traversed by the depressed pin until it reaches the switch 56 represents the linear distance from the pin-hole detector I8 to the shear drums Iii-I6, or the elapsed time required for the indicated defect or hole in the strip to reach the shear drums I6-I6.

The shear drum I6l drives a Contact device shown in detail in Figure 6 and indicated as a whole at 59 in Figure 3. This contact device includes a shaft 62 secured to a shaft extension of Shaft 62 carries a cam 65. for coaction with a pivotally mounted contact arm 66 movable into and out of engagement with a contact 84. An electrical impulse is passed through the contact 64 and arm 86 once for each revolution and at a definite point in each revolution of the shear drums |6-I8 or for each sheet sheared thereby.

The electrical control instrumentalities above referred to, when coordinated with the sheet feeding means and related electrical and mechanical devices to be presently more fully described, are effective to automatically route prime salable sheets to the prime sheet stationv I and defective sheets such as those having pin-holes therein to the reject station I2. Such routing is under control of a deilector gate 10 pivoted on a shaft 12. A solenoid 14 or equivalent electrically powered device is capable of shifting the defleetor gate so that in one position it routes the prime sheets to station I0 and in another position routes defective sheets to station I2.

In operation, assuming that the metal strip is traveling at its normal speed of about 600 to 800 feet per minute and a portion of the strip with a pin-hole defect arrives at the pin-hole detector I8, such hole indication is transmitted as an electric impulse substantially instantaneously A seals in through its own contacts "--68b and through normally closed contacts 1816b of relay 16. Thus the impulse from the timer 38 is transmitted to relay 88. The result of this action is to place the routing of the defective sheet under the precision control of the shear drum contact device 68.

When the shear drums I8--I6 shear the defective sheet, contacts 84-88 of device 59 are closed, thus energizing relay 18, the exciting current flowing through normally closed contacts 8th-86b of relay 86. Relay 18 then closes and seals in through its own contacts 1618d and normally closed contacts 88"--86b of relay 88. The closing of relay 18 thus definitely initiates the operation of the deilector gate 10 through energization of solenoid 14 at an exact time, controlled with great precision with respect to the exact time of shearing a particular defective sheet, regardless of Whether the pin-hole or defect is located centrally or adjacent one or the other ends of the sheared sheet.

When relay 16 is energized, contacts 16l and 1Gb open, deenergizing relay 60, thus resetting said relay 60 to condition it to handle the next impulse from the timer-actuated contact 56 so as to provide for the precision control of successive defective sheets.

The operation of the deilector gate actuating solenoid 14 is controlled as follows:

Relay 86 is energized and closes immediately upon the closing of contacts 16-16f of relay 16, thus energizing the deector-actuating solenoid 14 due to closing contacts SGL-8c'd and 86-86 of relay 86. The gate operating solenoid 14 remains energized only for the time interval required to deenergize relay 18 through the normally closed contacts 86'^88b, which deenergizes relay 88 upon the opening of contacts IBL-161, thereby restoring the entire electrical control system for a repetition of the hereinabove described cycle.

It is manifest that upon energization of the deector gate actuating solenoid 14, the deector gate 10 will be instantly rocked about its pivotal support 12 so as to move the same from the position of Figure 1 to the position of Figure 3,

thus directing the defective sheet with the pinhole therein to the guide apron 62, guiding said defective sheet into the nip o! pinch roll 84. which cooperates with the roller 88 over which the defective sheet conveyor I8 is trained. Thus the defective sheet is routed to the conveyor i3 which delivers it to the box I2 herein referred to as the defective sheet station.

In the alternative embodiment of the invention diagrammatically illustrated in Figure 7, I have illustrated a combination of control instrumentalities embodying certain reinements over the combination shown and described in connection with Figures 1 to 8 inclusive. When using the control of Figures 1 to 6 inclusive, it is necessary to precisely adjust the drum contact device I8 in such manner as to set the point in the cycle at which the contacts 84, 88 close with respect to the position occupied by the cutter blades on the shearing drums I8-I8. To overcome this. in the arrangement of Figure '7 a photoelectric relay 88 is installed to control with precision the actual time at which the gate-operating solenoid 14 will operate with respet to the sheared sheet.

The photoelectric relay 88 is of known conventional form, and is acuated in much the same manner as the pin-hole detector I8 hereinabove described, except that relay 88 is actuated by the light beam passing through the space or gap between .two adjacent sheared sheets. This relay 88 is located at an exact predetermined distance from the deflector gate 'I0n calculated to allow suillcient time to operate the deilector gate promptly upon the arrival of a defective sheet. Referring in detail to Figure 7, the impulse from the pin-hole detector I8 is handled by Ithe timer in the same manner described in connection with Figure 3. Relay 100 then is closed from pinwheel timer 38 and normally closed contacts |06 and |06b of relay |06, and seals in through contacts |00 and |00b of relay |00. Relay ||2 now closes through contacts 64-66 of the shear driven contact device and normally open contacts |00`4|00r of relay |00. Then relay ||2 seals in through its own contacts H2B-I Iib and normally closed contacts |06-|06b of relay |06. Relay |06 now closes through contacts H2O-H2d of relay ||2 and contacts M100-|00d of relay |00. Relay |00 seals in through its own contacts |06|06f and normally closed contacts |38"- |38t of relay |38. After relay |06 closes, relays |00 'and ||2 are deenergized upon the opening of normally closed contacts |06--|06b. This allows the handling of successive sheets as relays |00 and ||2 can operate from another impulse while relay |06 remains energized until the defective sheet reaches the photoelectric relay 98. When the defective sheet reaches the photoelectric relay 88, contacts Ilo- |42 close, which closes relay |38 through contacts |06|||6d of relay |06 and relay |30 energizes deilector gate solenoid 'I4a through contacts |38"-|3|lb and |38c and |380. An important` feature of the herein claimed inventionfwhich distinguishes over prior art arrangements is that prior devices, to the best of my knowledge and belief, always measure the amount of strip from a photoelectric detector to a deflector gate and operate the gate after the strip travels said measured amount, regardless of whether the hole or similar defect occurs in the middle or atsome other point in the sheared sheet. Thus in such prior art devices, when the pin-hole occurs near the leading end of the sheet, the detiector gate is actuated too late in point of time to properly route the defective sheet. Hence in the prior art arrangement, a prime sheet is frequently erroneously directed to the station for rejects, and the defective sheet, which should have been directed to the station for rejects, frequently is conveyed to the station for prime sheets. My improved precision control apparatus herein set forth and claimed prevents such undesirable occurrences.

The advantages of my precision control for sorting defective and prime sheets are -made available largely as the result of providing means whereby the circuits controlling the energization of the power device 14 for actuating the defiector gate are controlled jointly by the timing device 38 and the contact device 59 driven in synchronism with the shear drums |6'|6. Inthe device of my invention, when the portion of the strip with a pin-hole or like defect therein reaches the .shear drums l6-l6, the position of the blades may be anywhere with respect to the point at which the sheet is sheared. The contacts 64-66 of the shear-driven contact device close only momentarily at a point in the rotation of the shear drums Ili--IBEL approximately 15 before the knife blades come into registry to shear the sheet. 'I'hus in my improved apparatus. the `sheet with the hole therein may be said to be definitely selected and its position located with great precision by electrical control instrumentalities whose operations are controlled jointly by the timer 38 and the shear driven contact device 69. The position of the pin-hole or like defect with respect to the shearing point will therefore not affect the distance measured by the timer 38. Otherwise expressed, the electrical control instrumentalities shown and described herein may be said to be constructed and arranged to energize the electrically powered deector gate at a definite time predetermined with relation to the severing of the strip by the shear. Thus my invention recognizes a bothersome operating problem which has baiiled those skilled in the art for some time, and provides a satisfactory and novel solution for the problem.

' While the foregoing description and accompanying drawings illustrate preferred embodiments of the invention which an actual reduction to practice has demonstrated to be highly desirable, it is not to be construed that I am limited thereto, since various modications and substitutions of mechanical and electrical equivalents may be resorted to by those skilled in the art Without departure from the scope of the appended claims.

Iclaim:

1. 'I'he combination with means for feeding a continuous strip and a shear for cutting the strip into sheets of desired lengths, said feeding means being-in frictional contact with said strip to advance the same of a sheet classifier comprising respective stations adapted to receive prime and defective sheets, respective conveyors for delivering sheets to eachv of said stations, a deectcr effective in one position to route sheets to the conveyor serving the prime sheet station and in another position to route sheets to the conveyor serving the defective sheet station, a pin-hole detector responsive to light penetrating a pin-hole or similar defect in the strip, an electrically powered element for actuating said deector, and instrumentalities constructed and arranged to energize said electrically vpowered element at a definite/time predetermined with relation to the severing of the strip by said shear, said instrumentalities including a time delay device driven by said feeding means and a contact device driven by said shear.

2. The combination with means for feeding a continuous strip and a shear for cutting the strip into sheets of desired lengths, said feeding means being in frictional contact with said strip to advance the same of a sheet classifier comprising respective stations adapted to receive prime and defective sheets, respective conveyors for delivering sheets to each of said stations, a deiiector eiective in one position to route sheets to the conveyor serving the prime sheet station and in another position to route sheets to the conveyor serving the defective sheet station, a pinhole detector responsive to light penetrating a pin-hole or similar defect in the strip, an yelectrically powered element for actuating said defle'ctor, and electrical control instrumentalities responsive to said pin-hole detector constructed and arranged to energize said electrically powered element at a definite time predetermined with precision in relation to the exact time the strip is severed by said shear, said instrumentalities including a time delay device driven by said feeding means and a contact device driven by said shear.

3. The combination with means for feeding a 7 continuous strip and a shear for cutting the strip into sheets of desired lengths, said feeding means being in frictional contact with said strip to advance the same of a sheet classier comprising respective stations adapted to receive prime and defective sheets, respective conveyors for delivering sheets to each of said stations, a deilector effective in one position to route sheets to the conveyor serving the prime sheet station and in another 'position to route sheets to the conveyor 8 for setting said timer. a contact device driven by said shear, and an electrically powered element controlled jointly by said timer and said contact device for actuating said defiector.

5. The combination with means ior feeding a continuous strip and a rotary shear for cutting serving the defective sheet station, means for detecting a perforated defect in the strip. a power means for actuating said deiiector, and control instrumentalities responsive to said detecting means constructed and arranged to render said power means eective to actuate said delector at a definite time predetermined with precision in relation to the exact time said strip is severed by said shear, said instrumentalities including a time delay device driven by said feeding means and a contact device driven by said shear,

e. The combination with means for feeding continuous strip and a shear for cutting the strip into sheets of desired lengths, said feeding means including staggered straightening rolls defining a sinuous path for the strip, said rolls making a non-slip frictional driving contact with the continuous strip of a sheet classifier comprising respective stations adapted to receive prime and defective sheets, respective conveyors for delivering sheetsto each of said stations, a deiiector eective in one position to route sheets to the conveyor serving the prime sheet station and in another position to route sheets to the conveyor serving the defective sheet station, a pinhole detector responsive to light penetrating a pin-hole or similar defect in the strip, a timer driven by said rolls at a rate proportional to the strips travel, means responsive to said detector the strip into sheets of desired lengths, said feeding means including staggered straightening rolls making a non-slip irictional driving contact with the continuous strip of a. sheet classifier comprising respective stations adapted to receive prime sheets and defective sheets, respective conveyors for delivering sheets to each oi' said stations, a deflector effective in one positiongto route sheets to the conveyor serving the prime sheet station and in another position to route sheets to the conveyor serving the defective sheet station, a pin-hole detector responsive to light penetrating a pin-hole or similar defect in the sheet stock, an electrically powered solenoid operativeiy connected to and adapted to actuate said deiiector, a time;` driven by said rolls, a contact device driven by the shear, and electrical control instrumentalities governed jointly by said timer and said contact device for controlling the energization and deenergization of said solenoid;

RALPH L. DOWELL.

REFERENCES CITED lThe following references are of record in the ille of this patent:

UNITED STATES PATENTS 5 Number Name Date 1,383,858 Spiess Oct. 18, 1932 2,138,645 Rey Nov. 29, 1938 2,229,638 Chamberlin Jan. 28, 1941 2,363,577 Dexter Nov. 28, 1944 

